We aim to determine the structure of the 70S ribosome from Thermus thermophilus complexed with mRNA and tRNA analogs. Recently we have obtained improved crystals that diffract to at least 8 E resolution. Experiments will focus on (1) improving the diffraction quality and cryoprotection of these new crystals, (2) collection of a new native data set, and (3) extending the molecular replacement phases to the diffraction limit of the crystals. We will pursue MAD and MIRAS phasing by means of heavy atom clusters and conventional heavy-atom compounds to derivatize crystals.